2023 Open de Oeiras – Singles

Kaichi Uchida was the defending champion but lost in the quarterfinals to Juan Manuel Cerúndolo.

Zsombor Piros won the title after defeating Cerúndolo 6–3, 6–4 in the final.

Seeds
• # 🇫🇷 Adrian Mannarino (second round)

• # 🇫🇷 Alexandre Müller (second round)

• # 🇦🇹 Sebastian Ofner (semifinals)

• # 🇦🇷 Juan Manuel Cerúndolo (final)

• # João Sousa (first round)

• # 🇯🇵 Kaichi Uchida (quarterfinals)

• # 🇭🇺 Zsombor Piros (champion)

• # 🇮🇹 Andrea Vavassori (quarterfinals)